Invertebrate Phylogenetic Tree

1,500 species

Informal name: "sponges"

They lack true tissues, but are still defined as animals

Example Organism: Azure vase sponge (Callyspongia plicifera)

NOT a part of clade Eumetazoa or Bilateria because they do not have tissues

10,000 species

Includes corals, jellies, and hydras

They have radially symmtrical bodies

Example Organism: Sea wasp (Chironex fleckeri)

They are a part of clade Eumetazoa, but not Bilateria

Nearly 139,00 species

Six main groups: Platyhelminthes, Rotifera, Ectoprocta, Brachiopoda, Mollusca, and Annelida. These include flatworms, ectoprocts, rotifers, lamp shells, ribbon worms, molluscs, segmented worms, acanthocephalans, and cycliophoran

Known and indentified by molecular data, that also has the most diverse animal clade in terms of body form

Example Organisms: Sea mat (Membranipora membranacea) and the Giant squid (Architeuthis dux)

They are a part of clades Eumetazoa and Bilateria

Nearly 1,030,000 species

Two main groups: Nematoda and Arthropoda, which includes loriciferans, priapulans, tardigrades, velvet worms, roundworms, insects, crustaceans, and arachnids

They are the most species-rich animal group, proven by having more known species than all other protist, fungus, plant, and animal groups combined

Example Organisms: Parasitic nematode (Trinchinella spiralis) and Fruit flies (Drosophila melanogaster)

They are a part of clades Eumetazoa and Bilateria

About 59,085 species

Two main groups:Echinodermata and Chordata (three groups of chordata are invertebrates: they consist of lancelets, tunicates, and hagfishes), and includes hemichordata

Defined primarily by DNA similarities, not developmental similarities

Example Organisms: Sea stars (Asterios forbesii) and Sea cucumbers (Parastichopus californicus)

They are a part of clades Eumetazoa and Bilateria